PH HYDROPOWER DEVELOPMENT in the PHILIPPINES By P. L. Lopez, * MBA, MS Water Resources Engineering

Transcription

1 PH HYDROPOWER DEVELOPMENT in the PHILIPPINES By P. L. Lopez, * MBA, MS Water Resources Engineering Abstract The present policy on energy development is geared towards harnessing renewable and indigenous energy resource which can offer clean, abundant and efficient power supply for the country. A review of the current generation mix of the power system, especially the Luzon grid will establish a high dependency in imported fuel - oil and coal to power our generating plants. Thus, the policy of reducing dependence on imported fuel will depend largely on the success of tapping the alternative renewable and indigenous sources. The sustainable development era of the '90's brought fresh interest on the performance and commercial viability of indigenous and/or renewable sources of energy such as wind, solar, geothermal, natural gas and water power or hydropower. Among these alternative renewable sources, water or hydropower is the most readily available, and will produce clean domestic source of electricity - no carbon dioxide, sulfur dioxide, nitrous oxide or any other air emissions. The potential is available in most parts of the country that are mountainous and have high rainfall. In terms of production, hydropower leads as the most developed and more proven in terms of commercial viability. It is also more reliable, efficient and less expensive than geothermal, biomass, wind and solar energy, as will be shown later. ^Employed in the National Power Corporation as: Project Director, Hydropower BOT Projects, and Special Assistant to the President, Technical Review

2 Hydropowcr Fundamentals As can be seen and/or experienced, the roar of the waterfall suggests the power of water. The floodwaters rampaging through the river can uproot trees and destroy villages. However, the might of water is made even greater if it will flow through a steep slope of the river. As the name hydropower suggests, water in lakes, rivers and other reservoirs is harnessed or put to work to produce kinetic energy. Hydroelectric dams are built to generate electric power by directing water through high pressure tunnels/penstocks to the turbines, which are wheels with.carved blades as spokes. The falling water spins the blades of the turbines connected to generators. Hydropower, therefore, is influenced by both the quantity of water flowing at a certain rate (discharge Q in cubic meter per second) and the difference in elevations at the head start and tail end of the flow (head h in meters). Please refer to Figure 1., The basic formula for hydropower, therefore, is P (kw) = 9.81 n Q h where n is the combined efficiency of the machine; From the formula, the output depends upon the head of water, or height of stored water above the turbines. The higher the water, the more weight and pressure are exerted in the turbine blades. A second factor as mentioned is the volume of water throughout the year. The minimum flow in dry months fixes the amount of firm power which customers can rely upon regularly. Sometimes, extra power or runof-rivcr power, generated in wet season can be sold, usually at low rates.

3 Figure 2): The component civil structures of a typical hydropower project are (see 1. Depending on its height, the dam or weir is constructed for the purpose of impounding water (reservoir), create additional head and allow diversion of water; 2. The spillway is the structure that will pass the flood in excess of what can be stored in the reservoir. The spillway is usually designed to pass the maximum flood possible; 3. The intake structure allows entry of water from the reservoir or the river; 4. The power conduit which could either be a tunnel or an open channel or canal or pipes transports water from the reservoir to the turbine units inside the powerhouse; 5. The powerhouse or the power station houses the turbine, generator units and other associated equipment. 6. The tailrace is the structure which will conduct water after running the turbine back to the river; 7. The switchyard which will transform the kinetic energy generated to electric energy; 8. The associated transmission line which will conduct the electric energy to the nearest substation for distribution; Aside from the above component structures, some electrical and mechanical equipment are required: turbines, governors, generators, control and switching apparatus and transformers. There are two general types of hydropower development: the run-of-river and reservoir type. The reservoir type of development is a hydro with significant storage. Water are impounded behind the dam which are released later to generate

4 energy during peaking periods. On the other hand, the run-of-river type has no storage and the dam/weir will primarily divert water. Thus, the turbines will be run by whatever inflow in the river that is available. A variation to the reservoir type is the pumped storage where water from a lower reservoir is pumped to an upstream reservoir. An example of this type is the Kalayaan Pumped Storage Plant in Laguna sown in Figure 3. The water stored upstream is then used later on to generate during peaking periods. The principle in this scheme is that the energy used for pumping water is cheaper because it is an off-peak energy while the energy produced by the pumped storage plant during peak periods is of a higher value because it is needed during peak. Hydropower vs. Thermal Generation See Figure Investment, O &M Costs and Useful Life The hydropower project is capital-intensive, because of the many structures needed to be built. In addition, because of the required construction work, site investigation to be able to design the project is more extensive and expensive and implementation period is longer. The hydropower is also site specific, and therefore, the cost of access and the associated transmission lines may be considerable. Unlike the thermal power where fuel cost is significant, water which is the fuel for a hydro is free. It is also renewable as this is returned to the river after its use. The operating and maintenance cost for the hydro therefore is almost nil. H

5 However, this resource (rivers and lakes) is a patrimony of the nation. The exploitation therefore, of this resource by a private individual must not be viewed as perpetual. The economic life is also longer - 50 years compared to thermal which is between 15 to 30 years. Over the long term therefore, hydropower is the cheapest source considering the long useful life and the overall costs. 2. Water A vailability or Hydrology Risk As mentioned before, unlike the thermal power project where fuel cost is significant, water as fuel for hydropower is free. However, generation output depends on the volume of water available for the turbine. The amount varies, however, for any given time. 3. Hydropower Performance in the System The hydropower project can be designed to serve any place in the load curve. It can either be a base load plant, a peaking station or an intermediate load station. It is versatile enough to be able to be operated to serve the needs of the system. Please refer to Figure 5. There are two components of generation output associated with operation, namely, the firm energy or on-peak energy and the secondary or off-peak energy. The firm energy is that output which can be guaranteed (defined at 90 to 95% reliability) to meet a certain system requirement for a specified period of time. This energy can be dispatched during that period and, therefore, has a high value than the second type. Associated with this energy is the dependable or

6 guaranteed capacity which can actually displace an equivalent thermal plant capacity during operation of the system. The secondary, off-peak or excess energy is that output which can be generated over and above the firm when the availability of water warrants. This type of energy cannot be dispatched and is valued less than the firm, specifically at the cost of the thermal fuel used by an equivalent plant when that energy was utilized by the system. Hydropowcr Implementation - Stages of Development See Figure 6. There are four (4) major stages of implementation of a hydropower project. These are the: (1) Pre-(easibility or reconnaissance stage, (2) Feasibility and/or Definite Design stage, (3) Detailed Design stage, (4) Construction stage. Each stage takes the project a step forward in the development cycle, based on the findings from the actual and previous stages. The planning stages cover the pre-feasibility and feasibility study phases. The main purpose for the Pre-feasibility stage is to perform river basin planning analysis which will allow the identification and ranking of the attractive hydropower sites for a particular river. Afterwards, having identified and ranked the best sites, a Feasibility Study needs to be conducted for each of the attractive sites. This is to establish the viability of the project considering the technical, economic and financial considerations. It is imperative, therefore, that at the feasibility level, a more improved data base should be secured, by the conduct of site investigation works (drilling, survey, etc.), so that the engineering design and estimates will be of better reliability. 0

7 The Definite Design study will confirm the findings in regard to the scheme of development proposed in the Feasibility. This is most important if there are new information/data available which will affect the design and cost, hence, the financing. The Detailed Engineering stage, on the other hand, is for the purpose of developing the engineering drawings for construction, development of tender documents for bidding out the construction of civil works and procurement of the equipment, including the tendering process itself. The Construction stage covers the implementation of the project. This phase is difficult because of the many structures involved and the timing needed to have the structures completed in time for the installation of the equipment.. -I Status of Hydropower Development in the Philippines The National Power Corporation formulated the 1997 Power Development Program (PDP) to establish the plans of the Philippine Government to meet the future loads by the coordinated addition of necessary generation and transmission facilities. The PDP confirms the need for the on-going projects, identifies critical new projects and provides direction for future courses of action. For the period 1997 to 2010, the PDP indicates the need for new generating projects with capacity totaling to 11,126 MW. The PDP also projects that the demand for electricity is expected to grow at an average rate of 6.3 % for the next twelve years. To meet this growing demand and at the same time reduce dependence on imported fuel, the Government is considering indigenous and renewable alternative energy. One such alternative source is hydropower.

8 Prospects Over 12,500 MW have been identified in the country as potential hydropower projects for development. Of these, only 19% have been developed. Figure 7 shows the summary of the resource potential for hydropower. The summary of all existing and on-going hydropower projects are shown in Figure 8. For the future, the PDP has scheduled for commissioning a number of hydropower projects with a total capacity of 1,450 MW between years 2000 to In addition to these, a 50 MW window is made available every year for indigenous and small hydro projects. This is equivalent to MW capacity slated for entry into the system by 2000 to A summary of the PDP capacity additions are shown as Figure 9. BOT Tendering In line with the government's thrust to tap private capital in implementing infrastructure projects, NPC has been offering the hydropower projects to private developers through the Build-Operate-Transfer (BOT) Scheme. NPC realized that the developers who choose to invest in hydropower project face many risks. However, it had identified the specific risks at every stage of the power projects life cycle and their cost implication. It is believed that a hydropowcr project implemented by a private group would be successful once these risks are effectively managed and properly allocated to the different players involved in a BOT arrangement. NPC's experience in private hydropower was limited to the unsolicited mode or negotiation for rehabilitation projects such as Ambuklao, Binga and the new Casccnan multi-purpose project. Solicitation was only done three (3) years ago

9 for the twelve (12) small hydros with capacities from five to 50 MW. However, there was a low turnout and the prices received were high. This can be attributed to the pricing policy adopted by NPC wherein the hydrology risk an important component of hydro generation was borne by the proponent of the projects tendered. Only one was successfully negotiated--the 70 MW Bakun Hydroelectric Project. It is now under construction. Recently, NPC adopted several policies which will reduce the risks of the proponent to manageable levels and reasonably enable them to recover their investments in the shortest possible time. NPC's hydropower projects which are included in the country's Power Development Program (PDP) were offered for BOT implementation. Bids were received last February 1997 for about eight projects. NPC is now negotiating the Power Purchase Agreement with the lowest complying bidders for the projects and expects the award within the year. In fact, for the San Roque Multi-purpose Project, the PPA was already signed this month.

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11 Figure 1 to switchyards and transmission lines SAMPLE DESIGN OF HYDROPOWER PLANT

12 Figure 2 OVERFLOW ^HEADRACE OR CANAL FOREBAY PENSTOCK P > HPOWERLINES TAlLRACEi 1 --' PERSPECTIVE VIEW OF CANAL TYPE SCHEME

13 Figure 3 Pensto UPPER RESERVOIR PUMPING CYCLE < j = GENERATING CYCLE LOWER RESERVOIR IAGUNA0E8AY POWERHOUSE v " PUMP m. 2x5OnvV$«c. T U R S i N f i *, _,...'..; He»d \mvc) Z$h.$Q m ; tuscharge 2*6Om 3 /sec^ SCHEMATIC DIAGRAM OF KPSPP. KALAYAAN PUMPED STORAGE POWER PLANT

14 Figure 4 HYDRO/THERMAL PLANTS CHARACTERISTICS HYDRO THERMAL COAL GEOTHERMAL OIL RESOURCE INDIGENOUS & RENEWABLE IMPORTED INDIGENOUS & NON-RENEWABLE IMPORTED LOCATION STEEP RIVER/LAKE SITE SPECIFIC VOLCANIC AREA SITE SPECIFIC NEAR THE GRID STRUCTURES :.>:*ifx2.< CONSTRUCTION 5 TO 10 YEARS 3 TO 4 YEARS 2-3 YEARS 1 TO 3 YEARS ENVIRONMENTAL CONSTRAINTS INUNDATION AT THE RESERVOIR AREA AIR POLLUTION AIR POLLUTION AIR POLLUTION INVESTMENT COST HUGE. MEDIUM HUGE MEDIUM FUEL 0 & M FREE HIGH MEDIUM HIGH ECONOMIC LIFE YEARS YEARS YEARS 1 YEARS OPERATING MODE a < o _J i \ / \ BASED TO PEAK BASE BASE BASE TO PEAK! t

15 Figure 5 (kw) Daytime peak Lighting peak - - Daily load curve Reservoir type (Hydro) Reservoir type (Hydro) \ r K CO Thermal power 0 Run-of-the -river type and flat portion pondage type 12 time Example of daily load curve and power supply

16 Figure 6 HYDROPOWER DEVELOPMENT CYCLE Project Planning Project Implementation Rrbject Operation Definite Design Study /tngineen Detailed Engineering^ Work Drawings structiorrmanaa 1-3 years 4-6 years years

17 Figure 7 HYDRO RESOURCE POTENTIAL LOCATION *.S... ;& MW OWH 7 LUZON EXISTING PRE-FEASIBILITY FEASIBILITY DEFINITE DESIGN TOTAL ,273 3,444 1,922 1,950 8, ,818 14,895 6,907 6,185 31, EXISTING PRE-FEASIBILlPi' FEASIBILITY DEFINITE DESIGN TOTAL , EXISTING PRE-FEASIBILITY FEASIBILITY DEFINITE DESIGN TOTAL ,193 1,104 3, ,571 4,799 4,768 14, EXISTING PRE-FEASIBILITY FEASIBILITY DEFINITE DESIGN TOTAL ,278 4,732 3,252 2,046 12, ,440 20,097 12,508 6,414 47,

18 Figure 8 HYDROPOWER PLANTS IN THE PHILIPPINES LUZON GRID Existing NPC PowerP'fonts Botocan HE " Caliraya Unit 1-4 Majayjay, Laguna Lumban, Laguna Ambuklao Unit 3-4 Ambuklao, Bokod, Benguet ROL Barit Mini-hydro Sta. Justina, Buhi, Camarines Sur Binga Unit 1-4 Binga, Itogon, Benguet ROL Angat HE Norzagaray, Bulacan Pantabangan Unit 1-2 Pantabangan, Nueva Ecija Angat Aux. Norzagaray, Bulacan 1981 Masiway Pantabangan, Nueva Ecija 1982 Kalayaan 1/2 P.S. Kalayaan, Laguna Magat Unit 1-4 San Ramon, Isabela Total 1, Existing NanJtPC Power Plants 1993 HEDCOR Benguet PPA NMHC Benguet PPA NIA-Baligatan Isabela PPA 6.00 Total Casecnan Nueva Vizcaya and Pantabanga, Nueva Ecija BOT Bakun Benguet and llocos Sur BOT Kalayaan 3/4 P.S. Kalayaan, Laguna San Roque San Manuel, Pangasinan BOT llaguen B llagan, Isabela 88 no 2010 Agbulu Kalinga-Apayao Addalam Quirino Total 1, VISAYAS GRID NPC Power Plants Loboc Unit 1-3 Loboc, Bohol Amlan Unit 1-2 Amlan, Negros Oriental 0.80 ' Total Janopol Janopol, Bohol Total Qii?goin<g{NPC PowerPiants _2003 Timbaban "2003" Villa Siga Total MINDANAO GRID NPC Power Plants Agusan M.H. Agus VI Unit 1-5 Agus II UniTT-3~ _J ~J T985-86" Agus VII Unit 1-2 Agus V Unit 1-2 Agus IV Unit 1-3 Pulangui IV Unit 1-3 Agus I Unit 1-2 Total Madalag, Aklan, Panay Villa Siga, Antique, Panay Fuentes, Iligan City Marawi City, Lanao del Sur Fuentes, Iligan City Ditucalan, Iligan City Baloi, Lanao del Norte Maramag, Bukidnon Marawi City, Lanao del Sur PPA _ J004_ 2006 Tagoloan Bulanog-Batang Pulangui V Agus Total Impasugong, Bukidnon Talakag, Bukidnon Roxas, North Cotabato Baloi, Lanao del Norte

19 Figure 9 REVISION 2 OCT97 YEAR BACMAN II-2 GEO LUZON LEYTE-LUZON INTERCON. MASINLOC 1 COAL SUAL 1&2 COAL CASECNAN HYDRO MASINLOC 2 COAL BAKUN A/C HYDRO SAN PASCUAL COGEN ILIJAN (GREENFIELDS) KALAYAAN 3/4 PS SAN ROQUE HYDRO PEAKING PLANT A PEAKING PLANT B MID-RANGE PLANT A ILAGUEN B HYDRO 20 CAP 1, AWUtt. ACOTOON NPC POWER DEVELOPMENT PROGRAM INDICATIVE MW CAPACITY ADDITION (1997 NPC LOW FORECAST) VISAYAS - MID-RANGE PLANT B 600 VISAYAS PEAKING C AGBULU HYDRO MID-RANGE PLANT C VISAYAS BASELOAD B VISAYAS PEAKING D 200 TOTAL i_/ For main NPC Grids only; Excludes Small Islands _2y No contract yet; Subject to PPA negotiation between NPC and PNOC-EDC LEYTE-CEBU INTERCON. LEYTE GEO A LEYTE GEO B LEYTE-BOHOL INTERCON. UPRATING LEYTE-CEBU T/L MAMBUCAL GEO & TIMBABAN HYDRO VILLASIGA HYDRO PANAY BASELOAD CEBU BASELOAD A BOHOL BASELOAD SAMAR COAL CEBU BASELOAD B CEBU PEAKING PANAY PEAKING BOHOLPEAKING VISAYAS BASELOAD A VISAYAS PEAKING A VISAYAS PEAKING B msu i CAP , SO AWWAL ADomc* MINDANAO ZAMBOANGA DIESEL GEN SANTOS DIESEL MINDANAO GEO U MINDANAO SC-GT MINDANAO C. CYCLE MINDANAO COAL LEYTE-MINDANAO INTERC. TAGOLOAN HYDRO BUL.-BATANG HYDRO MINDANAO PEAKING A PULANGUIV MINDANAO MID-RANGE A AGUS III MINDANAO MID-RANGE B MINDANAO MID-RANGE C MINDANAO PEAKING B MINDANAO BASELOAD A MINDANAO BASELOAD B CM* WHUAt AOOtTlOM PHILIPP ANNUAL TT 790 1, Peaking Plant -15% Plant Factor and Below Mid-Range Plant % Plant Factor Baseload Plant - 70% Plant Factor and Above i